The work proposed here will provide the foundation for a rapid, inexpensive, non-culture based test for the quantitative detection of oral C albicans in HIV-positive patients. The primary experimental objective will be to create a set of short synthetic oligodeoxynucleotide probes that will hybridize specifically with the 18S rRNA of Candida albicans. Specificity will be verified by hybridization of each probe to slot blot filters containing RNAs from > 100 microorganisms that are found frequently in the oropharynx, skin or urogenital region. Furthermore, the probes wig be used to measure levels of C albicans in mouth rinses from immunocompromised patients. Probe assays will be compared with conventional diagnostic evaluations of candidiasis in these same patients. Results of this comparison will establish the feasibility of using probes as an alternative to culture for diagnosing candidiasis. If this approach proves to be efficacious, these probes win be used during Phase H to develop a rapid, non-radioactive assay for detecting and monitoring C albicans in persons at high risk for developing acquired immunodeficiency syndrome (AIDS). The final product will be a quantitative test for the doctor's office that can be performed in less than one hour at room temperature and that can provide an alternative for the much lengthier procedure of culturing.